1. Field of the Invention
The present invention relates to a microvalve, and in particular, to a valve that opens and closes an opening through a displacement member, and also relates to a valve seat member included in the valve.
2. Description of the Related Art
Generally, items such as mobile personal computers that include fuel batteries for electrical power are being developed. Liquid fuels, such as methanol and ethanol, are used as fuel, and by supplying the fuel to a reacting furnace via a micropump, the reacting furnace causes the fuel and air to react to generate electrical power. In this type of fuel battery system, an unintended flow of fuel in the forward direction due to gravity can occur and unnecessary fuel can be supplied to the reacting furnace even when the pump is stopped. This can lead to a surplus of electric power generation. Micropumps are equipped with check valves. However, the check valves are valves for stopping a reverse flow and cannot block a forward flow.
Japanese Unexamined Patent Application Publication No. 62-28585 discloses a piezoelectric active valve that includes a valve housing that includes a flow inlet and a flow outlet for a fluid, and a valve body that includes a tabular piezoelectric element. Specifically, the periphery of the valve body is fixedly held against the valve housing, and an opening is provided in the valve housing region facing the central portion of the valve body. As a result of an application of a voltage to the piezoelectric element, the valve body bends in the plate thickness direction and the opening can be opened and closed as a result of the bending.
In general, a valve seat member made of a soft material, such as rubber, is fixed to the opening since a sufficient seal is not produced by simply making the previously described valve body contact the opening of the valve housing directly. One method of fixing the valve seat is to use an adhesive to fix the valve seat to the opening of the valve housing. However, when the intended fluid is an organic solvent, such as, for example, methanol, which is used as a fuel for fuel batteries, there is a possibility that the adhesive will be corroded, the fixing will become unstable, and the bond will peel off. Furthermore, if the valve seat is fixed to the valve housing in a tilted state or in an off-center state, the valve seat and the valve body do not make proper contact and consistent sealing performance may not be obtained.